Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
ACS Nano. 2011 Oct 25;5(10):8346-51. doi: 10.1021/nn2033693. Epub 2011 Oct 11.
Silicon has a high specific capacity of 4200 mAh/g as lithium-ion battery anodes, but its rapid capacity fading due to >300% volume expansion and pulverization presents a significant challenge for practical applications. Here we report a core-shell TiC/C/Si inactive/active nanocomposite for Si anodes demonstrating high specific capacity and excellent electrochemical cycling. The amorphous silicon layer serves as the active material to store Li(+), while the inactive TiC/C nanofibers act as a conductive and mechanically robust scaffold for electron transport during the Li-Si alloying process. The core-shell TiC/C/Si nanocomposite anode shows ∼3000 mAh g(-1) discharge capacity and 92% capacity retention after 100 charge/discharge cycles. The excellent cycling stability and high rate performance could be attributed to the tapering of the nanofibers and the open structure that allows facile Li ion transport and the high conductivity and mechanical stability of the TiC/C scaffold.
硅作为锂离子电池的负极材料具有高达 4200mAh/g 的比容量，但由于其体积膨胀超过 300%以及粉碎，其迅速的容量衰减对实际应用构成了重大挑战。在这里，我们报告了一种用于 Si 负极的核壳 TiC/C/Si 惰性/活性纳米复合材料，该材料表现出高比容量和优异的电化学循环性能。非晶态硅层作为存储 Li(+)的活性材料，而惰性 TiC/C 纳米纤维则作为导电和机械坚固的支架，在 Li-Si 合金化过程中用于电子传输。核壳 TiC/C/Si 纳米复合材料负极在 100 次充放电循环后具有约 3000mAh/g 的放电容量和 92%的容量保持率。优异的循环稳定性和高倍率性能归因于纳米纤维的逐渐变细和开放结构，这使得锂离子的传输更加容易，同时 TiC/C 支架的高导电性和机械稳定性也得到了保持。
